(a) Field of the Invention
The present invention relates to a control signal part and a liquid crystal display including the control signal part.
(b) Description of the Related Art
A liquid crystal display is one of the flat display devices widely used at the present time. The liquid crystal display includes two substrates in which a plurality of electrodes are formed, a liquid crystal layer sandwiched between the two substrates, and two polarizing films for polarizing the light attached to each outward surface of the substrates. The liquid crystal display controls the light transmittance, so as to display picture images by applying different voltages to the electrodes while forming electric fields for varying the orientation of the liquid crystal molecules of the liquid crystal layer. In such a liquid crystal display, thin film transistors are formed in one of the two substrates, which is called a TFT substrate, and the thin film transistors switch the voltages applied to the electrodes.
A display region for displaying picture images is situated in the center of the TFT substrate. A plurality of signal lines, or a plurality of gate lines and data lines are formed in the horizontal and vertical directions, respectively. The gate lines and the data lines cross each other, thereby defining a plurality of pixel element regions. Each pixel element has a pixel electrode to which the data signal is applied via the data line. The thin film transistor sends the data signal transmitted via the data line to the pixel electrode by the gate signal transmitted via the gate line.
A plurality of gate pads connected to the gate lines and a plurality of data pads connected to the data lines are formed outside of the display region. These pads are connected to the external driving integrated circuits and receive gate signals and data signals from the external driving integrated circuits. In addition, the pads send the signals to the gate lines and the data lines.
A printed circuit board for gate signal transmission and a printed circuit board for data signal transmission are attached to the thin film transistor substrate using an anisotropic conducting film through a heat-compression process so as to send the gate signals and the data signals to the thin film transistor.
The thin film transistor and the printed circuit board for data signal transmission are connected by a data signal transmission film on which the data driving integrated circuit is mounted. The data driving integrated circuit converts an electric signal into a data signal and sends the data signal to the data line. Also, the thin film transistor and the printed circuit board for gate signal transmission are connected by a gate signal transmission film on which the gate driving integrated circuit is mounted. The gate driving integrated circuit converts an electric signal into a gate signal and sends the gate signal to the gate line.
Herein, gate control signals for controlling the gate signal may be output from the printed circuit board for data transmission instead of from the printed circuit board for gate transmission. And these gate control signals may be transmitted to the gate signal transmission film. In such a case, gate control signal wires are formed on the data signal transmission film which is connected to the printed circuit board for data signal transmission and gate control signal connection wires corresponding to the gate control signal wires are formed on the thin film transistor substrate. Then, the gate control signal wires of the data signal transmission film are connected to gate control signal connection wires of the thin film transistor. Accordingly, the gate control signals are transmitted to the gate driving integrated circuit on the gate signal transmission film from the data signal transmission film.
The gate control signals are various kinds of control signals such as a gate-on-voltage, a gate-off-voltage and a common voltage for reference voltage to the differences of the data voltages in the thin film transistor.
These gate control signals input into the gate driving integrated circuit, while driving the liquid crystal display, have various magnitudes of voltage and are transmitted through gate control signal connection wires. The gate control signal connection wires are arranged abreast and closely on the thin film transistor substrate. Accordingly, a high voltage signal wire transmitting a high voltage such as the gate-on-voltage and a low voltage signal wire transmitting a low voltage such as the gate-off-voltage are arranged abreast and closely.
In this arrangement of the wires, a potential difference is formed between the high voltage signal wire and the low voltage signal wire while driving the liquid crystal display. This potential difference causes an electrolysis reaction when moisture permeates into the wires during the manufacture and operation of the liquid crystal display. As a result, damage is caused to the high voltage signal wire, and this damage results in the production of inferior devices.
It is an object of the present invention to provide a control signal part and a liquid crystal display including the control signal part which prevent the damage of wires due to electrolysis.
This object is provided, according to the present invention, by forming high voltage redundancy wire(s) at one side or both sides of a high voltage signal wire, thereby to form equipotential around the high voltage signal wire.
According to one aspect of the present invention, a control signal part includes a first signal wire transmitting a first signal voltage, a second signal wire transmitting a second signal voltage smaller than the first signal voltage, and a first redundancy wire transmitting the same voltage as the first signal voltage. The first redundancy wire is formed between the first signal wire and the second signal wire. The control signal part may also include a second redundancy wire that transmits the same voltage as the first signal voltage. Herein, the first redundancy wire is located at one side of the first signal wire and the second redundancy wire is located at the other side of the first signal wire.
The first redundancy wire may be connected to the first signal wire or separated from the first signal wire. At least one of the first redundancy wire and the second redundancy wire may be connected to the first signal wire. And both the first redundancy wire and the second redundancy wire may be separated from the first signal wire.
The first redundancy wire may be formed by less oxidative conductive materials than conductive materials for forming the second signal wire. Also, the first redundancy wire may be formed by conductive materials such as one from the copper family, silver family, chromium family, or molybdenum family, including nitride chromium and nitride molybdenum. In the alternative, the first redundancy wire may be formed by ITO or IZO.
According to another aspect of the present invention, a liquid crystal display includes a display region, which includes a gate line, a data line crossing the gate line thereby defining a pixel element region, a thin film transistor connected to the gate line and the data line in the pixel element region, and a pixel electrode electrically connected to the thin film transistor; a driving integrated circuit part including a gate driving integrated circuit for outputting a gate signal to the gate line and a data driving integrated circuit for outputting a data signal to the data line; a control signal part for controlling the driving integrated circuit part, the control signal part including a first signal wire transmitting a first signal voltage, a second signal wire transmitting a second signal voltage smaller than the first signal voltage, and a first redundancy wire transmitting the same voltage as the first signal voltage, where the first redundancy wire is formed between the first signal wire and the second signal wire.
The control signal part may further include signal wires for driving the gate driving integrated circuit. Even further the control signal part may include signal wires for driving the data driving integrated circuit.
The first signal voltage may be a gate-on-voltage or a power supply voltage, and the second signal voltage may be a gate-off-voltage or a ground voltage.
A second redundancy wire that transmits a voltage equivalent to the first signal voltage may be included. Herein, the first redundancy wire is located at one side of the first signal wire, and the second redundancy wire is located at the other side of the first signal wire.
The first redundancy wire may be connected to the first signal wire, or separated from the first signal wire. And at least one of the first redundancy wire and the second redundancy wire may be connected to the first signal wire. Moreover, the first redundancy wire and the second redundancy wire may be separated from the first signal wire.
The first redundancy wire may be formed by less oxidative conductive materials than conductive materials for forming the second signal wire. Also, the first redundancy wire may be formed by conductive materials such as one from the copper family, silver family, chromium family, or molybdenum family, including nitride chromium and nitride molybdenum. The first redundancy wire may be formed by ITO or IZO.
And the first redundancy wire may be formed by conductive materials for forming the gate line, the data line, or the pixel electrode.
The first signal wire may have a wire structure in which a first wire is connected to a second wire. Herein, the first wire is connected to the gate driving integrated circuit and the second wire is connected to the data driving integrated circuit. The first wire may be formed by conductive materials for forming the gate line or the data line and the second wire may be formed by conductive materials for forming the data line or the gate line.
The first redundancy wire may have a wire structure in which a first wire is connected to a second wire. Herein, the first wire is connected to the gate driving integrated circuit and the second wire is connected to the data driving integrated circuit. The first wire may be formed by conductive materials for forming the gate line or the data line and the second wire may be formed by conductive materials for forming the data line or the gate line.
The signal wires of the control signal part may include a lower wire having a pad and may be formed by conductive materials for forming the gate line. The signal wires of the control signal part may further include a first insulating layer covering the lower wire, a first contact hole exposing one end of the lower wire, and an upper wire having a pad and being formed by conductive materials for forming the data line. Herein, the upper wire is connected to the lower wire through the first contact hole. Also, the signal wires of the control signal part may further include a second insulating layer covering the upper wire, a second contact hole exposing the pad of the upper wire, and a third contact hole exposing the pad of the lower wire, and an auxiliary pad covering and being connected to the pads of the lower and the upper wires through the second and third contact holes.